These days, flying insects are seen as genuinely agile aircraft fitted with a parsimonious brain capable of visually navigating in unpredictable environments. Understanding, how such tiny animals work, would allow engineers to figure out different issues in relation with drones miniaturization. To turn a drone into a robot of 1 kg, conventional avionics can be employed by miniaturizing avionic systems, but at the expense of their flight autonomy. However, turning a drone into a robot of a mass between 1 g and 500 g requires an innovative approach taking inspiration from flying insects both with regard to their flapping wings propulsion system and their visiosensory system mainly based on motion in order to orientate in space, to navigate, or to see and avoid obstacles.